Ultrafiltration of Myoglobin using Surface-Sulfonated Polysulfone Hollow Fiber

The usage of ionic polysulfone (PSF) hollow fiber for the ultrafiltration of protein was investigated. The surface of polysulfone hollow fiber was sulfonated through the Blanc chloromethylation reaction to become anionic. Characterization of the modified hollow fiber was performed including ion exchange titration, pure water permeation, and molecular sieving measurement. The performance of ultrafiltration of protein was evaluated using myoglobin at various pH values. The results show that the water contact angles and hydraulic resistance are markedly decreased, indicating that the surface-modified PSF hollow fibers are more hydrophilic. In addition, the retention of myoglobin depends on the pH of the solution. At a pH higher than the isoelectric point of myoglobin, both hollow fiber and the protein have the same charge sign, and both the flux of the solution and the retention are the highest. The sulfonated PSF hollow fiber may be used as a biomaterial for protein separation and purification.